mohammed morsi is calling for a national dialogue with the opposition this weekend. he also accused some opposition members working with mubarak regime. potential for more death in syria on a larger scale is growing tonight. chief washington correspondent james rosen has disturbing news about weapons of mass destructions. >> a regime helicopter calltured in the skies above syria in the unverified amateur video unloadss something. likely a defensive flare. but the moment epitomizes the threat of nuclear weapons that the syrian people now live. rebel forces are now taking the fight directly to the assad regime inside the capital damascus with a deadly explosion near the arab red crescent building and pitch battles for key airfields outside the city. >> it is clear regime forces are being grounded down and they are losing. >> president bashar assad already killed estimated 40,000 people. president obama top aids will fear the fighting take on gruesome character. >> we remained very concerned. very concerned. as the opposition advances on damascus. that the regime might